In a typical cellular radio system, user equipments (UEs) communicate via a radio access network (RAN) to one or more core networks. FIG. 1 shows a schematic diagram of a Radio Network Subsystem (RNS) 100. The RNS 100 has a Radio Network Controller (RNC) 101. Each RNS 100 has one or more Node B 102 which are similar in function to a Base Transmitter Station of a Global System for Mobile communication (GSM) radio access network. UE 103 may be mobile within the radio access network. Radio connections (indicated by the straight dotted lines in FIG. 1) are established between the UE and one or more of the NodeBs in the UMTS Terrestrial Radio Access Network (UTRAN). The UE comprises various types of equipment such as mobile telephones (also known as cellular or cell phones), laptops with wireless communication capability, personal digital assistants (PDAs) etc. These may be portable, hand held, pocket sized, installed in a vehicle etc and communicate voice and/or data signals with the radio access network.
In recent years, portable terminals and smartphones are widely used, and there is a consistent desire for high-capacity data transfer using a portable communication network. In the network, UE transmits/retransmits uplink data according to acknowledgement (ACK) or Negative-acknowledgement (NACK) from a base station (BS) indicating success or fail of reception of the data. If the ACK/NACK cannot be transmitted normally, the network throughput will be reduced.
Therefore, there is a need to effectively enhance network throughput with a new ACK/NACK information transmission mechanism.